After a thorough search, I found the same question on the internet. Please refer to the attached picture. If it's the same one with yours, then the answer is letter C - The constant 10 refers to the cost of setting up the food stall even if no cheeseburger was sold.
It is like a fixed cost that is incurred by the food stall that they need to pay for not considering the sales or income they would earn.
It is like a fixed cost that is incurred by the food stall that they need to pay for not considering the sales or income they would earn.